Does laser photobiomodulation prevent hyposalivation in patients undergoing head and neck radiotherapy? A systematic review and meta-analysis of controlled trials

Introduction: Head and neck radiotherapy can cause hypofunction of the salivary glands. Many studies report that laser photobiomodulation (PBM) is able to minimize radiation-induced hyposalivation, yet there is no consensus about its effects. Objective: To carry out a meta-analysis of controlled clinical trials that used PBM to prevent radiation-induced hyposalivation. Methods: A systematic search was performed through Embase, Medline/PubMed, Cochrane, EBSCO, Scopus, LILACS and Web of Science databases. The strategy included comparisons of the effect of PBM with placebo/clinical follow-up on unstimulated and/or stimulated salivary flow in patients undergoing head and neck radiotherapy. Results: Six clinical trials were included, five of which were used for meta-analysis. Evidence was observed be-tween the use of PBM and increased unstimulated salivary flow (MD 0.20 mL/min, 95 % Cl 0.10-0.30, I-2 = 96 %, p < 0.00001) and in stimulated salivary flow (MD 0.27 mL/min, 95 % CI 0.080.46, I-2 = 95 %, p < 0.00001). Conclusion: PBM appears to minimize radiation-induced hyposalivation.